Electrically operated oscillatory system for timepieces



Oct. 2, 1962 A. BEYNER ETAL 3,056,253

ELECTRICALLY OPERATED OSCILLATORY SYSTEM FOR TIMEPIECES Filed y 26, 1961 JAM/[mom ANDRE/ 5mm ANDRE HU6 RENE MEISTER BY AGENTJ United States Patent O 3,056,253 ELECTRICALLY OPERATED OSCILLATORY SYSTEM FOR TIMEPIECES Andr Beyner, Neuchatel, Ren Meister, Bienne, and Andr Hug, Neuchatel, Switzerland, assignors to Ebauches S.A., Neuchatel, Switzerland, a Swiss firm Filed May 26, 1961, Ser. No. 112,994 Claims priority, application Switzerland June 10, 1960 1 Claim. (Cl. 58-28) The present invention relates to an oscillatory system for timepieces, whose oscillations are maintained electrically.

This oscillatory system is characterized in that it comprises a circular plate made of ferro-magnetic material, carried by the shaft on which the said system oscillates, and an annular mount constituting a fixing frame, and made of non-magnetic material, to which the said plate is fixed, the said mount comprising two internal lugs which are diametrally opposite one another and to which a permanent magnet and a balancing counter-weight are fixed respectively, the said magnet being in contact with the said plate.

The drawings show by way of example one form of embodiment of the subject of the invention.

FIGURE 1 is an axial sectional view of an oscillatory system for a timepiece, and

FIGURE 2 is a sectional view thereof taken on the line 11-11 of FIGURE 1.

The oscillatory system illustrated comprises a shaft 1 rotating between two bearings 2 carried by the frame of the timepiece movement. This shaft carries two co-axial circular plates 3 and 4 made of ferro-magnetic material and spaced apart from one another 'by a spacer element 5 which is also made of ferro-magnetic material and is force-fitted on to the shaft. These plates are crimped to the spacer element.

The plate 3 carries a permanent magnet 6 and a balancing counter-weight 7. This magnet and this counterweight are fixed to a common mount constituted by a ring or fixing frame 8 made of non-magnetic material such as, for example, nickel silver, and the said ring is forcefitted about the plate 3 but could also be welded electrically. The said ring comprises two inner lugs 80:, which are arranged diametrally opposite one another and in whose housings 9 there are force-fitted the magnet 6 and the counter-weight 7 respectively. The magnet is in contact with the plate 3.

The system is provided with a spiral-type return spring 10.

The advantages of the present construction reside in the simplicity and the facility with which it permits of adjustment. Thus, the system can be balanced by slightly enlarging a central hole 11 provided in the counterweight 7. The adjustment of its moment of inertia is easily obtained by retouching the external diameter of the ring 8. This adjustment thus does not affect the magnetic circuit in any way.

The electric elements for maintaining the oscillatory movements of the system have not been shown in the drawings, since they do not form part of the present invention. They comprise fixed coils which are in relative movement with respect to the air gap 12, provided between the magnet 6 and the plate 3, during the oscillations of the system. The magnetic circuit forms a loop situated in a radial zone with respect to the axis of oscillation; it passes through the two plates 3 and 4, through the central spacer element 5, and is closed at the air gap 12.

It should be noted that this system is astatic, and that it is not influenced by the vicinity of ferromagnetic parts, since the magnetic losses exhibit a circular symmetry. The disturbing torques thus do not depend on the amplitude, but produce a constant braking torque independent of the amplitude of the oscillations.

What we claim is:

'In an oscillatory system for timepieces, the oscillations of which are maintained electrically, a shaft on which the said system oscillates, a circular plate made of ferromagnetic material which is carried by the said shaft, an annular mount forming a fixing frame and consisting of non-magnetic material, to which the said plate is fixed, the said mount comprising two inner lugs which are situated diametrally opposite one another, a permanent magnet, extending parallely to the said shaft, in contact with the said plate, a balancing counter-weight, said magnet and said counter-weight being fixed respectively to the said lugs, and a second circular plate coaxial with the first plate, carried by the said shaft, also made of ferro-magnetic material, said second plate being situated at a certain distance from the end of the said magnet.

References Cited in the file of this patent UNITED STATES PATENTS 2,800,763 Ensign et a1 July 30, 1957 2,986,683 Lanet et al. May 30, 1961 FOREIGN PATENTS 1,074,506 Germany Ian. 28, 1960 

